Cryptocurrency is a digital currency that can be used to buy goods and services. Cryptocurrency was made to make transactions safer and more efficient without using a third party and decentralizing the process. Which removes the risk related to the third party and reduces cost since the third party is not there. All cryptocurrency use block chain technology which ensures that you can track the use of this currency, reducing the risk of frauds.
Each time someone buys a cryptocurrency its value increases since more money went in increasing the average value. So each time a cryptocurrency falls it means that someone took their money out of the cryptocurrency. So the rise and fall of a cryptocurrency depends on the supply and demand of the currency.